This is a multidisciplinary study of the processes through which biological, behavioral, and environmental factors influence the survival of infants to age one. The study is based on the analysis of linked data from hospital records, birth and death certificates, and aggregate U.S. Census data. The study population consists of approximately 16,000 births that occurred in a large urban hospital (Johns Hopkins, Baltimore) between 1979 and 1986. Drawing on the perspectives of social science, obstetrics, pediatrics and health services research, the study will consider not only late fetal, perinatal and later infant mortality, but also the intermediate outcomes of low birthweight, pre-term delivery, and intrauterine growth retardation. The study will examine the determinants of pregnancy outcome for blacks and whites separately, and will also examine differences in the structure of these determinants between adolescents and older mothers, and adolescents in a special intervention program and those receiving routine prenatal care. The study will be based on a interactive life-course model of fetal and child development, which permits an examination of the interplay of the various factors that influence pregnancy outcome. A series of multivariate statistical techniques will be appled to the data, in order to allow an assessment of the relative influence of these factors both on the intermediate outcomes and on mortality.